I've tested Zango before and it's pretty good, the setup is a lot of like AdWords in that you choose keywords and target sites. I'm sure someone is doing this and sorry if I'm away your niche but I would assume, as I have not personally tried the campaign, that since the Zango system is setup for "pageviews" you could target ebay and ebays related sites/forums and use cookies stuffing tools. If you target users who are on ebay.com and stuff them, there is a pretty good chance of making revenue from that person.
All you would have to do is setup a BANS site for Zango to pop-up when someone was on ebay or ebay related site and stuff them.
I'm sure this would go for A LOT of niches but this one seems like it would be the most promising especially with the PepperJam partnership.
Zango is all about trial and error, just like adwords so it would take some time but overall I think it would be a pretty easy idea.